Driven by the external power, floating algal patches in the open Taihu Lake would drift into Meiliang Bay and Zhushan Bay located in the northern part of Taihu Lake. And the input of exogenous algal patches would aggravate the outbreak of algal blooms in local areas. Based on the self-developed situ observation technique of algal patches drift. We investigated the variation characteristics of algal patches horizontal drifting velocity at different time scales in Zhushan Bay, Lake Taihu. The results showed that the diurnal variation range of algal drift ratewes (0.0793±0.0135)~(0.146±0.0318)m/s during the period of observation, and the eigenvalues of the northern and eastern component of drifting velocity of algal patches were -0.0896~0.0247m/s and -0.0157~0.0029m/s, respectively, which reflected significant time difference. The daily mean value of the drift rate based on situ observation exhibited a zigzag alternating characteristic, that was, an increase-decrease-re-increment reciprocating cycle, with a variation range of (0.0499±0.0141)~(0.1580±0.0120)m/s, and the drift direction was mainly northward. The inter-monthly variation of algal patches horizontal drifting velocity was obvious, From June to August, the proportion of drift to the east gradually decreased, while the proportion of drift to the west gradually increased. During this period, the drift direction was mainly northward. The drift rate of the algal blooms was the smallest in early June, with an average of 0.0680m/s. It reaches the maximum in the first half of July, with an average of 0.1350m/s. The drift rate from mid-July to late August fluctuated around 0.0800m/s.